Hey Guys And Gals, Here is my 100% Achievement Guide & Full Walkthrough for Wailing Heights!
This is at the start of Act 2, once you go outside from the police station, walk to the left a touch and you see a zombie reading a newspaper by the water fountain.
Talk to him once for a bit, exhaust the dialogue options.
Once thats finished, just talk to him again straight away and the achievement will unlock!
Go to 24:40 in my video to see where and how this unlocks.
Hope This Helps!